hypertrophy & atrophy

What is hypertrophy?

Hypertrophy is an increase and growth of muscle cells. Hypertrophy is achieved through exercise and in humans the most common way to achieve hypertrophy is through lifting weights. There are two types of muscular hypertrophy, myofibril and sarcoplasmic. 

Myofibril hypertrophy refers to the process of increasing the number of myofibrils in the muscle which helps to increase the strength of the muscle and the speed that the muscle reacts.

Sarcoplasmic hypertrophy refers to the increase of the glycogen storage in the muscle. The increase of the storage increases the muscles stamina as well as making the muscles appear larger, but does not effect the strength of the muscle.

There is another type of muscle hypertrophy that is the result of a genetic mutation of the Myostatin gene. By having a reduction in the Myostatin in the body there is no limit to the size of the muscle mass. This is often referred to as “double muscles” and some breeds are more predisposed to this condition. One example of this is the Bully Whippet.

What is atrophy?

Atrophy is when the muscles of your dog’s body weaken or waste away. It usually affects a dog’s back legs, but it can also occur in the head or the belly.

Muscle atrophy often occurs after surgery or from an injury and can be quite obvious to see, however, sometimes atrophy can occur slowly over time and this may be masked or hidden by a long coated dog.

Atrophy may also be as a result of disruption in the nerve pathways to the muscle, which will lead to the muscles not being activated. For instance, in the event of paralysis the muscles will not be receiving their signals to activate.

There are a few breeds that are susceptible to muscle atrophy, due to their likelihood to suffer from certain types of myopathy (a disease that can cause damage to muscles). For example, German Shepherds are prone to suffer from fibrotic myopathy, which is a disease that can effect their thigh muscles, causing their “dipped” appearance of their hind quarters. Some sighthounds are also at a higher risk of atrophy. For instance a breed such as a greyhound is at risk of exertion myopathy, which is as a result of overworked muscles. 

Hypertrophy:

This is an example of muscular hypertrophy in a dog.

This is a Bully Whippet and you can quite clearly see the effect of the condition.

This dog will have reduced flexbility and may also have some pain associated with the condition.

atrophy:

This is an example of muscular atrophy in a dog.

This dog has recently undergone Cruciate Ligament surgery and due to the bed rest it has lost muscle mass in the left hind limb.

This dog will be able to increase mass and strength with therapy.

what causes hypertrophy?

There are a few things that can cause hypertrophy. They are:

  • Exercise - this can cause muscle growth

  • Genetic predispostion - such as seen in the Bully Whippet

  • Overcompensation due to another muscle being injured and the dog having to use other muscles more to compensate

what causes atrophy?

The most common cause of atrophy is surgery or injury, however there are other things that can cause this:

  • Paralysis - this can interrupt the signals between the muscle and the brain

  • Natural ageing process - the body produces less growth hormones in later life

  • Reduced activity of the muscles - ie from ageing, injury, pain etc

  • poor diet

  • spinal cord or nerve damage

what are the symptoms of hypertrophy?

  • reduced flexibility and increased rigidity

  • altered gait as a result of the reduced flexibility

  • localised pain as a result of the hypertrophy

  • postural changes

  • the body may look unbalanced as a result of one side having more mass

what are the symptoms of atrophy?

  • reduced strength of the muscle

  • weight loss

  • limping or dragging their paw

  • unbalanced gait or loss of coordination

  • progressive weakness in the limbs

  • difficulty weight bearing

  • postural changes

  • increased lethargy

  • crossing of the legs while walking or standing

how can massage help with both conditions?

  • To avoid muscle atrophy it is important to keep your dog on a regular exercise routine, even in their later years. A diet that is nutritious, high in fat and high in protein is preferable, and avoiding foods that are high in carbs and fillers

  • Massage helps muscles return to their normal working order and will aid to reduce pain felt, which leads to these conditions

  • Increases flexibility and mobility in the muscle, which will reduce the effects of both of these conditions

  • Massage will bring new nutrients to the muslce, these nutrients include nutrients used in muscle building to aid with atrophy

  • Improves the rate of healing of the muscle, which will help with recovery post injury or surgery

  • Reduces negative effects of orthopaedic conditions such as osteoarthritis, which can cause muscle atrophy

  • Reduces stiffness to the muscle, which will help with daily activities and exercise

  • Improves energy release around the body to aid with daily activities

Contraindications (reasons to not massage or to alter the massage) to be aware of - if your dog is showing any signs of the following then please let me know and then we can discuss a treatment schedule to work around or outside of the particular issue.

  • Epilepsy

  • The severity of the condition

  • The level of inflammation in the area (heat therapy should be avoided if inflammation present)

  • Skin irritations such as eczema

  • Bruises

  • Open wounds

  • High blood pressure

  • Diabetes

  • Cardio-vascular conditions

  • Broken bones

  • Pregnancy